Earlier this year when scientists discovered a whale graveyard in the Atacama region in Chile, we knew that we had embarked on exciting times in marine mammal science as our knowledge of extinct species and cetacean evolution was about to be radically expanded – what we didn’t realise at the time was just how rapidly that expansion would happen.
On the other side of the Pacific Ocean, researchers at Waseda University in Japan have determined that contrary to popular belief, dolphins have been around for twice as long as we had originally thought. By studying a fossil of a skull fragment from a dolphin, found in a Japanese river back in 1970, they were able to date dolphin origins all the way back to the late Miocene period some 8 to 13 million years ago.
This discovery has helped dispel one of the great mysteries of dolphin evolution as until now there has always been an inconsistency between the fossil records of dolphins (to date all have shown dolphins to have originated less than 6 million years ago) and molecular studies (which suggested that they actually originated between 9 and 12 million years ago).
This new (or more correctly, old) species of dolphin has been named Eodelphis kabatensis – and it has the honour of being the earliest yet the latest dolphin species to be described to science.
The location of the fossil find is also important as although this work is in its infancy, and more specimens need to be discovered, the presence of Eodelphis in the Pacific Ocean suggests that dolphins may have had their origins in the Pacific. Then again … perhaps there are even older dolphin fossils out there somewhere just waiting to be discovered?